Positionable gas injection nozzle assembly for an underwater pelletizing system

ABSTRACT

A positionable gas nozzle assembly for injecting and directing pressurized air or other gas having an inert nature into a pellet slurry so as to increase the velocity of the slurry from a pelletizer to and through a dryer. The variably positionable nozzle can be inserted, retracted and/or intermediately positioned to facilitate start-up of the pelletization process, reduce or eliminate pellet hang-up points, maximize and optimize the velocity of the pellet slurry throughput, and to adjust the aspiration level of the pellet slurry such that the internal heat of the pellets is retained for improved degrees of crystallization and/or drying.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to underwater pelletizingsystems and, more particularly, to a gas injection nozzle for use withsuch systems.

2. Description of Related Art

Those skilled in the art have found it beneficial, and sometimesnecessary, to produce pellets that crystallize, either partially orfully. To help achieve that crystallization, the assignee of the presentinvention has disclosed the use of a nozzle through which pressurizedair or other gas can be injected into the pellet slurry to help decreasethe retention time of the pellets in the transportation liquid betweenthe upstream pelletization process and the downstream drying andsubsequent processes in U.S. Pat. No. 7,157,032; U.S. Patent ApplicationPublication Nos. 2005/0110182 and 2007/0132134; World Patent ApplicationPublication Nos. WO 2005/051623, and WO 2006/127698, all of which areowned by the current assignee of the present invention and areincorporated herein by reference as if fully set forth in theirentirety.

Similarly, WO 2007/027877 discloses the use of a nozzle through whichpressurized air or other gas can be injected into the pellet slurry tofacilitate aspiration of the liquid from the pellets in the pelletslurry. Moisture content of the pellets is lowered by reducing theretention time of the pellets in the transportation liquid between theupstream pelletization process and the downstream drying and subsequentprocesses. The reduced retention time also results in more of theinternal heat of the pellets formed being retained, and thus reduces themoisture available for uptake by the pellets. This application, alsoowned by the current assignee of the present invention, is alsoincorporated by reference herein in its entirety.

Under certain conditions, pellets can clump or form agglomerates duringthe pelletizing process. The formation of pellet agglomerates can havemany causes, of which sticky pellets is both common and frequent. Whenthese agglomerates form they have the tendency to get caught inso-called “hang-up points”, a term used herein to describe locationsthroughout the process where pellets and/or agglomerates of pellets tendto get hung-up and remain, often forming an obstructive build-up. As anexample, agglomerates of pellets can form when “drooling”, excessiveflow of molten material through the die holes, occurs at the die plate,thus creating an undesirably large pellet. Large pellets are not theonly problem. Pellets of desirable size can create a problem as well.Sticky pellets, or pellets that are still soft, that come into contactwith the nozzle can be “smashed” and stick to the nozzle due to theirstickiness and the velocities at which they are traveling. Eventuallymore and more pellets come into contact with those stuck on the nozzleand pellets begin to adhere to each other creating a mass of pellets,also referred to as an agglomerate. Eventually the mass of pellets canbecome large enough to disrupt the flow of transport liquid and pelletsthrough the transport pipe. This disruption can force the pelletizationprocess to be stopped.

One such hang-up point has been found to exist in pelletization linesutilizing the apparatus and process of inserting pressurized gasdescribed in the afore-identified patents and applications, namely thepoint at which the gas insertion nozzle is located within the pellettransport pipe. According to these prior embodiments, the nozzle used toinject the air is as illustrated in FIG. 1 and generally designated bythe reference numeral 200. The prior art fixed nozzle tube 210 isattached, preferably by welding, into elbow 202 at juncture 214. Thisfixed nozzle assembly 200 cannot be removed to facilitate start-up. Itcan further serve as a potential source for occlusion by pelletagglomeration as it cannot be maneuverably positioned to permit freeflow of the pellet slurry about the periphery of the fixed nozzle pipe210. Similarly, the fixed position limits the degree to which the air orother gas being injected can be controlled through valve regulation.

Therefore, a need exists for a positionable nozzle that can be adjustedto optimize the crystallization and/or drying of pellets produced by anunderwater pelletizing system.

SUMMARY OF THE INVENTION

In view of the foregoing, it is an object of the present invention toprovide a positionable nozzle through which pressurized gas isintroduced into the transport apparatus of an underwater pelletizer toincrease the velocity of a pellet slurry being transported from apelletizing process to and through a drying process while controllingthe dynamics of the slurry flow through changes in the position of thenozzle.

Another object of the present invention is to provide a positionablenozzle having a nozzle tube and collar that slides within a housingattached to a seal transition collar and affixed to an elbow within thetransport pathway between the pelletization apparatus and the dryingapparatus.

Still another object of the present invention is to provide apositionable nozzle in accordance with the preceding objects that ismanually or mechanically adjustable between at least a fully inserted orforward position and a fully retracted position.

A still further object of the present invention is to provide apositionable nozzle in accordance with the preceding objects that can bemanually or mechanically adjusted to inject pressurized gas in one ormore intermediate or partially inserted positions.

A further object of the present invention is to provide a positionablenozzle in accordance with the preceding objects that is angularlypositioned within the lumen of the elbow to which it is attached suchthat the angle ranges from approximately 0° from the centerline of thedownstream assembly to a maximum angle defined by contact of the outsideof the nozzle tube with the inside surface of that downstream assembly.

Yet another object of the present invention is to provide a positionablenozzle that is concentrically centered about the centerline of thedownstream equipment.

Still a further object of the present invention is to provide apositionable nozzle through which pressurized gas is introduced thatincreases the velocity of a pellet slurry being transported from apelletizing apparatus to and through a drying apparatus such that theinternal heat of the pellets is retained to facilitate drying of thepellets such that the moisture content of the pellets leaving the dryingapparatus is less than approximately 1.0% by weight, more preferablyless than 0.5% by weight, and most preferably less than 0.25% by weight.

An additional object of the present invention is to provide apositionable nozzle through which pressurized gas is introduced toincrease the velocity of a pellet slurry being transported from apelletizing apparatus to and through a drying apparatus such that theinternal heat of the pellets is retained to facilitate both drying andcrystallization of the pellets.

A further object of the present invention is to provide a positionablenozzle in accordance with the preceding object through which pressurizedgas is introduced that increases the velocity of a pellet slurry beingtransported from a pelletizing apparatus to and through a dryingapparatus such that the pellets leaving the drying apparatus arecrystallized at least 20% by weight, more preferably at least 30% byweight, and most preferably at least 40% by weight.

Yet a further object of the present invention is to provide apositionable nozzle that can be retracted at least partially to preventpellet hang-up during start-up of the pelletization process, and thatcan be moved forward to expedite the flow of the pellet slurry into andthrough the transport pipe and to facilitate the aspiration of thetransport liquid away from the pellets as they move through thetransport pipe.

A still further object of the present invention is to provide apositionable nozzle having any of a number of cross-sectional shapes,inner surface variations or internal structures in order to producespecific desired effects on the flow of the pellet slurry.

In view of these and other objects, the present invention is directed toan injecting device for use with an underwater pelletizer apparatus thatextrudes and cuts polymer strands into pellets which are conveyed as awater and pellet slurry through transport piping to a centrifugal dryer.The injecting device includes a positionable nozzle assembly having anadjustable injection position to introduce a pellet speed expediter intothe water and pellet slurry to increase a velocity of the pellet slurryto and through the dryer such that more internal heat of the pellets isretained. The nozzle assembly is adjustable between a fully insertedposition in which a nozzle tube of the assembly is positioned forwardlywithin the transport piping and a fully retracted position in which thenozzle tube is withdrawn from the transport piping to provide whollyunobstructed flow of the slurry through the piping. Preferably, thepositionable nozzle assembly is configured so that the nozzle tube canbe positioned manually or mechanically, at various intermediatepositions between the fully inserted forward position and the fullyretracted position.

These benefits together with other objects and advantages which willbecome subsequently apparent reside in the details of construction andoperation as more fully hereinafter described and claimed, referencebeing had to the accompanying drawings forming a part hereof, whereinlike numerals refer to like parts throughout.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cut-away and cross-sectional illustration of a prior artfixed nozzle configuration.

FIG. 2 is a schematic illustration of an underwater pelletizing systemincluding an underwater pelletizer and transport piping with apositionable nozzle connected to a centrifugal dryer in accordance withthe present invention.

FIG. 2 a is an enlarged view illustration of the positionable nozzle ofFIG. 2.

FIG. 3 is a cut-away and cross-sectional illustration of a portion ofthe positional nozzle and transport piping of FIG. 2 a with the nozzletube in a retracted position.

FIG. 4 is a cut-away and cross-sectional illustration of a portion ofthe positional nozzle and transport piping of FIG. 2 a with the nozzletube in an inserted forward position.

FIG. 5 is a schematic top view of a portion of the positional nozzle andtransport piping of FIG. 2 a with the nozzle tube in the insertedforward position.

FIG. 6 a is an illustration of the forward orifice of a nozzle tubecontaining perpendicularly oriented straight fins in accordance with thepresent invention.

FIG. 6 b is an illustration of the forward orifice of a nozzle tubecontaining perpendicularly oriented contoured fins in accordance withthe present invention.

FIG. 6 c is an illustration of a semicircular forward orifice for anozzle tube in accordance with the present invention.

FIG. 6 d is an illustration of a conchoidal to C-shaped forward orificefor a nozzle tube in accordance with the present invention.

FIG. 6 e is an illustration of a nozzle tube with tapered terminus inaccordance with the present invention.

FIG. 6 f is an illustration of a nozzle tube with a decreasingly conicaltapered bore in accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Although preferred embodiments of the invention are explained in detail,it is to be understood that other embodiments are possible. Accordingly,it is not intended that the invention is to be limited in its scope tothe details of constructions, and arrangement of components set forth inthe following description or illustrated in the drawings. The inventionis capable of other embodiments and of being or carried out in variousways. Also, in describing preferred embodiments, specific terminologywill be resorted to for the sake of clarity. It is to be understood thateach specific term includes all technical equivalents which operate in asimilar manner to accomplish a similar purpose. Where possible,components of the drawings that are alike are identified by the samereference numbers.

The positionable nozzle assembly according to the present inventionhelps to enhance the crystallization of various polymeric materials andalso facilitates drying of those and other materials while eliminating apossible hang-up point for agglomerates that has been encountered withprior designs. With pressurized air or other gas injected into thepellet transportation pipe, the velocity of the pellet slurry isincreased. The result is a decrease in time that the pellets aresubjected to the transport liquid due to that increased velocity as wellas the aspiration of transport liquid away from the surface of thosepellets. Due to the increased velocity, the retention time of thepellets in the transport liquid is less, allowing the pellets to retainmore internal heat than had they been subjected to the transportationliquid for a longer period. In effect, it is the increase in retainedinternal heat that aids in the crystallization of the pellets. Thiseffect is further enhanced by the aspiration of the transport liquidaway from the surface of the pellets such that loss of heat to thetransfer liquid is reduced.

To achieve the maximum throughput of the pellets, the present inventionallows the geometry and positioning of the nozzle to be adjusted. Thisis important to the velocity at which the slurry is transported from thepelletizer to the dryer which, in turn, impacts the efficiency of thesystem in separating the pellets from the transport liquid by aspirationand increasing the amount of internal heat retained by the pellets.Changing the geometry and positioning of the nozzle can also serve toalter the flow pattern of the slurry through the transport pipe,creating more or less turbulence to meet specific requirementsassociated with the material being processed.

Turning now to FIG. 2, the positionable nozzle in accordance with thepresent invention, generally designated by the reference numeral 100, isassembled into the transport piping, generally designated by thereference numeral 15, that connects the pelletization apparatus 10 tothe drying apparatus 20 and any subsequent post-processing. A meltingand mixing apparatus, not shown, connects to the pelletizer 10 to whichis attached inlet pipe 12. Transport liquid is introduced through inletpipe 12 into the cutting chamber of pelletizer 10 where it mixes withthe pellets to form the pellet slurry. The pellet slurry exits throughoutlet pipe 14 into and through sight glass 16 and then past thepositionable nozzle assembly 100 in transport piping 15. A pellet speedexpediter is injected and directed into the transport piping through thepositionable nozzle assembly 100 to reduce the time the pellets aresubjected to the transport liquid. The pellet speed expediter ispreferably air in view of its inert nature and ready availability.However, other gases having inert characteristics such as nitrogen orsimilar gases could be used. The expedited pellet and transport liquidpasses through transport pipe 18 into and through dryer assembly 20wherein the pellets are dewatered and dried. Details of the expeditedpellet and transport liquid follow below.

The melting and mixing apparatus, not shown, can be any prior knownapparatus or combinations thereof and can include, without being limitedthereto, melt vessels, single screw extruders, twin screw extruders,static mixers, continuous mixers, Banbury-type mixers, and the like asis known to those skilled in the art.

The pelletizer 10 can be a water ring pelletizer, an underwaterpelletizer, and the like, and is preferably an underwater pelletizerfitted with an extrusion die as is well known to those skilled in theart. Transport liquid can be any liquid and is preferably water.Optionally, the water or other transport liquid can contain additivesincluding, but not limited to, flow modifiers, coatings, defoamers,cosolvents, and the like. As used herein, when references are made to“water” in connection with the transport liquid, such references areintended to refer to any liquid suitable for use as a transport liquid,with or without additives, and not just water.

The materials being pelletized and transported in accordance with thepresent invention can be polymers, waxes, and the like that areconventionally processed by pelletization. As examples, the materialscan include polyolefins, polyesters, polyethers, polythioethers,polyamides, polyamideimides, polysulfones, polycarbonates,polyurethanes, fluoropolymers, vinyl polymers, biodegradable polymers,and copolymers thereof. Preferably the materials are those that aretypically crystallized before further processing, and more preferablythe materials can be dried to a moisture content of less than 1% byweight and crystallized to a level of at least 20%. Even morepreferably, the materials can be dried to a moisture content less than0.50% moisture by weight and crystallized to a level of at least 30% byweight, and most preferably the materials can be dried to a moisturecontent less than 0.25% by weight and crystallized to a level of atleast 40% by weight.

Alternatively and optionally, the materials to be pelletized can containany conventional filler and combinations of fillers and/or otheradditives as are known to those skilled in the art. The fillers caninclude cellulosic powders and/or fibers, biomaterials including powdersand fibers, and the like.

The dryer 20 in FIG. 2 can be at least one of a dewatering device,filtration device, vibratory dewatering device, fluidized bed, tumbledryer, centrifuge, dryer, centrifugal dryer, and is preferably aself-cleaning centrifugal dryer. Post-processing can include but is notlimited to at least one of cooling, enhanced crystallization, heating,additional drying, sizing, solid state polycondensation or solid statepolymerization, packaging, and the like as is well known to thoseskilled in the art.

One embodiment of the positionable nozzle assembly 100 according to thepresent invention is shown in more detail in the enlarged view of FIG. 2a. The assembly includes a valve 104, a pipe 106, a check valve 108, anda nozzle tube 110 which is partially inserted into elbow 102 and notvisible, as indicated by the dotted line. The nozzle tube 110 isinserted into elbow 102 at insertion point 112 and extends into thelumen of elbow 102 to the juncture 114 of elbow 102 and effluent pipe116. Inlet gas line, not shown, is attached to valve 104, which ispreferably a ball valve.

The pellet slurry passing through sight glass 16 (see FIG. 2) passesthrough influent pipe 118 and into and through elbow 102, where itinteracts with the pressurized gas, preferably air, before passing intoeffluent pipe 116 and through valve 120. Influent pipe 118, elbow 102,and effluent pipe 116 can be a single piece of pipe that has beenmodified by bending to shape the elbow and to allow insertion of nozzletube 110. Preferably, however, the influent pipe 118, elbow 102, andeffluent pipe 116 are separate components that are attached together,such as by threaded engagement or welding. Influent pipe 118 andeffluent pipe 116 can be the same diameter as elbow 102, or they can beof different diameter than the elbow 102 in which case they arepreferably tapered to the diameter of elbow 102. According to apreferred embodiment, influent pipe 118 and elbow 102 are the samediameter and effluent pipe 116 taperingly decreases in diameter from thejuncture 114 with elbow 102 to the attachment with pipe extension 122leading to and connecting with valve 120. Valve 120 is connected,preferably by threaded engagement or by welding, to transport pipe 18.

Optionally, effluent pipe 116 and pipe extension 122 can bedisconnectedly attached by a quick disconnect connection 124 asillustrated in FIG. 2 a. The quick disconnect connection 124 can be anysuitable pipe quick-disconnect assembly. Such a connection facilitatesease of access to the elbow and nozzle assembly for inspection,cleaning, maintenance, and repair as needed.

Influent pipe 118, elbow 102, effluent pipe 116, and nozzle tube 110 arepreferably made of metal including tool steel, vanadium steel, carbonsteel, hardened steel, stainless steel, nickel steel, and the like, butcan also be made of wear resistant industrial grade plastic. Thesecomponents are more preferably made of stainless steel and mostpreferably made of low carbon stainless steel.

Check valve 108 is preferably placed between a receiver tank (not shown)and the elbow 102 and prevents water and pellets from backing up intothe receiver tank. Check valve 108 allows pressurized air or other gasto flow through it, but when air or other gas is not passing through it,pressure from the transport liquid will cause check valve 108 to shut,thus preventing a back flow of transport liquid and pellets.Alternatively, an automated valve, preferably an electromechanical valvewith an actuator, can be substituted for check valve 108.

Valve 104 allows the operator to control the flow rate of thepressurized air or other gas. Preferably a ball valve, valve 104 isattached, such as by bolting, welding, or threaded attachment, to nozzletube 110. Valve 104 is most preferably attached sequentially to pipe106, check valve 108, and nozzle tube 110. Optionally and alternatively,an electromechanical valve can be substituted for both valve 104 andcheck valve 108.

Valve 120 can further regulate the velocity of the pressurized air orother gas. Valve 104 can be closed to allow conventional pelletizationprocessing without the need for pressurized gas injection. Both valve104 and valve 120 are optional and either can be used alone without theother. Preferably, valve 104 is present for regulation of thepressurized gas and more preferably, valve 104 and valve 120 are used insynergistic combination for the greatest control and regulation of thepressurized air or other gas.

The positionable nozzle assembly is preferably located as shown in FIG.2 and detailed in FIGS. 2 a, 3, 4, and 5. Transport pipe 18, FIGS. 2 and2 a, is preferably straight with the air or other gas being injectedinto elbow 102. FIGS. 2 a, 3, and 4, are preferably in line with theaxis of transport pipe 18 to maximize the effect of the injection on thepellet slurry and to uniformly aspirate the pellet slurry. The locationof elbow 102, or equivalent structure such as a “Y” configuration, ispreferably in the first elbow after the pellet slurry leaves pelletizer10. However, the elbow 102 can be located in an optional elbow furtherfrom pelletizer 10, not shown, and prior to dryer 20. Optionally amultiplicity of nozzle tubes can be inserted in at least one elbow tosynergistically facilitate transport to and through at least onetransport pipe 18.

FIG. 3 illustrates a portion of the positionable nozzle assembly 100 ina fully retracted position relative to the elbow 102. As shown, therearward end of the nozzle tube 110 is surrounded by collar 122 whichguides the rearward end as the nozzle tube slides within cylindricalhousing 128. The nozzle tube 110 and collar 122 can be of a single bodyconstruction, but preferably the nozzle tube 110 and collar 122 areseparate components attached together, such as by welding. The nozzletube 110 and collar 122 are preferably welded at each end of the collar,at weldment 124 and weldment 126.

The nozzle tube 110 and collar 122 are variably positionable and arefreely slideable through the housing 128. The forward end 130 of thehousing 128 is threadingly attached to a seal transition collar 132which is attached to elbow 102 at juncture 112. The forward end of thenozzle tube 110 is slidingly supported within the central bore 133 ofthe collar 132. Within the housing 128 and circumferentially positionedabout the nozzle tube 110 is a tension spring 134. At least one guidepin 136 is attached to the collar 122. The guide pin 136 aligns with andis positionable within at least one groove 138 in housing 128 asdetailed in FIG. 5. For larger transport pipes and nozzle assemblies, itis preferable to have at least two guide pins 136 that alignpositionably within at least two respective grooves 138 in the housing128 to provide greater adjustment capability. Groove 138 is linearlyelongate with the length of housing 128 and forms at least one angularrecess 140 as shown in FIG. 3, or multiple recesses 140, 141 as shown inFIG. 5.

Returning to FIG. 3, tension spring 134, preferably a coiled spring,seats on the forward face of collar 122 as well as on the rearward faceof the seal transition collar 132. In FIG. 3, the tension spring 134 isexpanded for the retracted position of the nozzle tube assembly. FIG. 4shows the tension spring 134 compressed in the forwardmost position ofthe positionable nozzle assembly 100 in which the nozzle tube 110 isfully inserted into the lumen of elbow 102. As shown, when fullyinserted the collar 122 is received in the housing 128, and guide pin136 is locked in angular recess 140 as more clearly illustrated in FIG.5. When the nozzle tube is only partially inserted, on the other hand,the guide pin 136 would be locked in angular recess 141.

Nozzle tube 110 preferably is sealingly positioned in seal transitioncollar 132, FIGS. 3 and 4. Sealing is achieved by any mechanical meansknown to those skilled in the art including O-rings, “quad” rings,mechanical seals, and the like without being limited thereto. Preferablysealing is achieved using at least one O-ring 142 retained in acircumferential groove 144 in seal transition collar 132. O-ring 142fits sealingly about the diameter of nozzle tube 110 such that nozzletube 110 can be sealingly and slidably positioned through the at leastone O-ring 142. Preferably at least two O-rings 142 are sealinglypositioned in at least two respective circumferential grooves 144. Mostpreferably, a multiplicity of O-rings 142 are sealingly positioned in anequal multiplicity of circumferential grooves 144.

FIG. 5 illustrates a portion of the positionable nozzle assembly 100 inwhich the nozzle tube 110 is fully inserted into the lumen of elbow 102approximately flush with juncture 114 as comparably illustrated anddescribed above for FIG. 2 a. Collar 122 has been inserted into housing128 and guide pin 136 has moved through groove 138 to be firmlypositioned in angular recess 140.

Nozzle tube 110 can be generally positionable throughout a range fromoutside the exterior of elbow 102 within the lumen of seal transitioncollar 132 to at least the juncture 114 and optionally beyond.Preferably the fully retracted position is approximately flush with theexterior of elbow 102 and the fully inserted position is approximatelyat the juncture 114.

Movement of the nozzle tube 110 within the positionable nozzle assembly100 can be accomplished by any suitable method including manual,pneumatic, electronic, automated, and hydraulic, and can optionally bewith programmable logic control, PLC, and any combination thereof. Thenozzle tube 110 can be moved at any time and is preferably manuallymovable. Manual control necessitates specific placement of thepositioning as determined by the angular recess 140 positions. Ifmovement is automated, however, a multiplicity of positions can be madeavailable. Use of guide pin(s) 136 and the associated groove(s) 138 andangular recesses 140 and 141 in FIG. 5, for example, would not beexpected to be necessary for control by automation.

Preferably nozzle tube 110 can be placed in a retracted position duringthe “start-up” of pelletizer 10 to eliminate its presence as anobstruction in the transport piping 15. Unwanted agglomerates can easilybe formed during the beginning phase of the pelletization process andallowing the pellet slurry to use the full inside diameter of transportpiping 15 as facilitated by the retraction of nozzle tube 110 isbeneficial.

Positionable nozzle assembly 100 is designed to allow the operator(s) toinject pressurized air or other gas into transport pipe 18 while havingthe option to adjust the location of the nozzle tube 110 in relation tothe transport pipe 18 and the elbow 102. The extent to which nozzle tube110 can be retracted and inserted while still creating the desiredaspiration is dependent upon, but not limited to, at least one of flowrate, pellet to transport liquid ratio, transport liquid temperature,diameter of the elbow 102 relative to the transport pipe 18, distancebetween the elbow 102 and the dryer 20, and the type of material beingpelletized.

It is to be understood, as illustrated in FIGS. 2 a, 3 and 4, that theoutside diameter of nozzle tube 110 will be smaller than the insidediameter of elbow 102 at juncture 114, for example. In this regard, thespace in the lumen should be large enough to allow the combined largestdimensions of at least two pellets, as measured using pellets of themaximum size for the particular pelletizing system, to pass between theexterior of the nozzle tube 110 and the interior of elbow 102 atjuncture 114. Stated another way, the clearance area between the outsidediameter of the nozzle tube and the inside diameter of the elbow lumenis large enough to allow at least two pellets, each having a maximumdimension for the pelletizer, to pass side by side therethrough withoutblocking, or clogging in, the clearance area. By way of example, withoutbeing limited thereto, one embodiment of the present invention is thatof a 0.75 inch nominal nozzle tube 110 in combination with a 2 inchnominal nozzle influent pipe 118 to elbow 102, a 2 inch nominal elbow102, and a 1.5 inch transport pipe 18 from elbow 102 to dryer 20.Another embodiment is that of a 0.75 inch nominal nozzle tube 110 incombination with a 3.0 inch nominal elbow 102, and a further embodimentis that of a 0.5 inch nominal nozzle tube 110 in combination with a 2.0inch nominal elbow.

The orientation of the nozzle tube 110 in relation to the juncture 114of elbow 102 in FIG. 2 a can be concentrically centered about thecenterline of that juncture 114, or reflected above the centerline,below the centerline, to the right or left of the centerline, or at anyangle circumferentially about that centerline where the angle formedbetween the centerline of the nozzle tube 110 and the centerline of thejuncture 114 of elbow 102 can range from 0° to a maximum deflection.Maximum deflection is defined as that degree of deflection at which theexterior of nozzle tube 110 touches the interior of the juncture 114 ofelbow 102 and/or any apparatus into which the nozzle tube 110 extendsdownstream of that juncture 114 of elbow 102. Preferably the nozzle tube110 is concentrically positioned and collinear about that centerline ofjuncture 114 of elbow 102. It is understood that the centerline ofjuncture 114 of elbow 102 is colinear with the centerline of transportpipe 18 downstream of that juncture 114.

The forward orifice 146 of nozzle tube 110 can be of any shape includinground, square, rectangular, oval, polygonal, and the like and ispreferably round. The diameter of the forward orifice 146 can be largerthan, smaller than, or equal to the diameter of the nozzle tube 110 andis preferably equal thereto. When the diameter of forward orifice 146 isnot equal to that of the nozzle tube 110, the diameter taperinglyincreases or decreases, respectively, for only that portion of thenozzle tube 110 that is not in contact with the most proximate O-ring142; see FIGS. 3 and 4. The diameter of the distal orifice 146 cannot,however, be larger than the inside diameter of the seal transitioncollar 132. A decreasing taper 150 is illustrated in FIG. 6 e for theterminus of nozzle tube 110. Similarly the forward orifice 146 can besemicircular as illustrated in FIG. 6 c or conchoidal to C-shape as inFIG. 6 d.

The inside of nozzle tube 110 can be provided with many differentvariations including but not limited to at least one of spiraled,contoured, rifled, or tapered inner surfaces, and many combinationsthereof. FIG. 6 f illustrates a conically tapered nozzle tube 110wherein the taper decreases toward the forward orifice 146.

The inside of nozzle tube 110 can also or alternatively contain one ormore fins 152 as shown in FIGS. 6 a and 6 b. The fins can be straightand angled at 90° relative to the circumference of the nozzle tube 110,as illustrated in FIG. 6 a, or at a lesser angle. Similarly, the finscan be bent or contoured relative to the circumference of the nozzletube 110 as illustrated in FIG. 6 b. The fins can be of any lengthranging from less than to equal the length of the nozzle tube 110, andtheir height cannot exceed the radius of nozzle tube 110. Preferably thefins 152 are less than the length of the nozzle tube 110 and are smallerin height than the radius of nozzle tube 110. When multiple fins areincluded, they can also be placed at any angle in relation to each otherand can be the same or different in construction. The purpose of thefins is to facilitate the creation of more turbulent flow within thetransport pipe 18. More particularly, the flow of the aspirated pelletslurry can range from laminar to turbulent. Without intending to bebound by any theory, the injection of the air or other gas into thepellet slurry aspirates the transport liquid from the pellets such thatthe transport liquid is transported in a laminar fashion along the innersurface of the transport pipe 18 while the vapor mist and pellets arepropagated in a more turbulent flow through the center of transport pipe18 along the length of the transport pipe 18. In some cases, moreturbulent flow may be desired, in which case fins may be advantageouslyadded.

In accordance with the present invention, pressurized air or other gascan flow through nozzle tube 110 continuously or intermittently, mostpreferably continuously. This pressurized gas can be used to convey thepellets at a high velocity as described. This high velocity gas flow canbe achieved using compressed gas producing a volume of flow exemplarilyof at least 100 cubic meters per hour using a standard valve 104 forregulation of the pressure to at least 8 bar through the transport pipe18. The pipe 18 is standard pipe diameter, preferably 1.5 inch pipediameter. To those skilled in the art, flow rates and pipe diameterswill vary according to the throughput volume, material compositionincluding filler, transport liquid temperature, level of crystallinitydesired, level of moisture desired, and the size of the pellets andgranules. The high velocity gas effectively contacts the pellet waterslurry, generating water vapor by aspiration, and disperses the pelletsthroughout the slurry line to propagate those pellets at increasedvelocity to the dryer 20, preferably at a rate of less than one secondfrom the pelletizer 10 to the exit of the dryer 20. The high velocityaspiration produces a mixture of pellets in an air/gas mixture which mayapproach 98-99% by volume of the gaseous mixture. Through adjustment ofthe nozzle tube insertion depth as well as the addition of surfacevariations inside the nozzle, the flow characteristics of the slurrywithin the transport piping can be altered.

Returning now to FIG. 2 a, the angle formed between the vertical axis ofinfluent pipe 118 and the longitudinal axis of the transport pipe 18 canvary from 0° to 90° or more as required by the variance in the height ofthe pelletizer 10 relative to the height of the entrance 22 to the dryer20 as shown in FIG. 2. This difference in height may be due to thephysical positioning of the dryer 20 in relation to the pelletizer 10 ormay be a consequence of the difference in the sizes of the dryer andpelletizer. The preferred angle range is from about 30° to 60°, with themore preferred angle being about 45°. The enlarged elbow 24 into thedryer entrance 22 facilitates the transition of the high velocityaspirated pellet/water slurry from the incoming transport pipe 18 intothe entrance 22 of the dryer 20 and reduces the potential for pelletagglomeration into the dryer 20.

The outside surface of nozzle tube 110 and the inner lumens of influentpipe 118, elbow 102, effluent pipe 116, and transport pipe 18 can becoated with surface treatments to reduce abrasion, erosion, corrosion,wear, and undesirable adhesion and stricture. These surface treatmentscan be at least one of nitriding, carbonitriding, and sintering.Similarly the heretofore mentioned surfaces can undergo high velocityair and fuel modified thermal treatments, electrolytic plating,electroless plating, flame spray, thermal spray, plasma treatment,electroless nickel dispersion treatments, and electrolytic plasmatreatments, singly and in combinations thereof. These treatmentsmetallize the surface, preferably fixedly attach metal nitrides to thesurface, more preferably fixedly attach metal carbides and metalcarbonitrides to the surface, even more preferably fixedly attachdiamond-like carbon to the surface, still more preferably attachdiamond-like carbon in an abrasion-resistant metal matrix to thesurface, and most preferably attach diamond-like carbon in a metalcarbide matrix to the surface. Other ceramic materials can be used andare included herein by way of reference without intending to be limited.The coating thickness should not exceed approximately 0.002 incheswithout appropriate modification to the diameters of the parts throughwhich the coated surface must pass sealingly.

While the invention has been disclosed in its preferred forms, it willbe apparent to those skilled in the art that many modifications,additions, and deletions can be made therein without departing from thespirit and scope of the invention and its equivalents as set forth inthe following claims.

1. An injecting device for use with an underwater pelletizer apparatusthat extrudes and cuts polymer strands into pellets, said apparatusincluding piping to introduce water into said pelletizer and a transportpathway to transport a water and pellet slurry out of said pelletizerand to a centrifugal dryer for drying said pellets, said injectingdevice comprising: a positionable nozzle assembly having a movablenozzle tube for introducing a pellet speed expediter into said water andpellet slurry to increase a velocity of the pellet slurry to and throughthe dryer such that more internal heat of the pellets is retained, saidnozzle tube being selectively movable to different positions between afully inserted position in which the nozzle tube is positioned forwardlyto be within the piping and a fully retracted position in which thenozzle tube is withdrawn from the piping to provide unobstructed flow ofthe slurry through the piping and to prevent pellet hang-up on thenozzle tube.
 2. The injecting device according to claim 1, wherein saidtransport pathway of said underwater pelletizer apparatus includes anoutlet pipe coupled to said pelletizer through which the slurry ispassed to a transport pipe that conveys the slurry to the dryer, saidnozzle tube being positioned between said outlet pipe and said transportpipe.
 3. The injecting device according to claim 2, wherein said outletpipe and said transport pipe are joined by an angled joint into whichsaid movable nozzle tube can extend.
 4. The injecting device accordingto claim 3, wherein said positionable nozzle assembly further comprisesa seal transition collar affixed to said angled joint, a housingattached to said seal transition collar, and a sliding collar that isfixed to said nozzle tube and received within said housing, said slidingcollar and said nozzle tube being freely movable within said housing. 5.The injecting device according to claim 4, wherein said housing includesa tension spring positioned circumferentially around the nozzle tube andseated on a forward face of the sliding collar and a rearward face ofthe seal transition collar, said tension spring being compressed as saidmovable nozzle tube is advanced with respect to said angled joint. 6.The injecting device according to claim 5, wherein said housing has atleast one groove that extends parallel with said movable nozzle tube,said groove having at least one angled recess, said sliding collarhaving a guide pin attached thereto that is positionable within saidgroove and, when received in said angled recess, locks the nozzleassembly at a set degree of tension spring compression associated with aparticular insertion position.
 7. The injecting device according toclaim 6, wherein said pellet speed expediter is pressurized gas and saidnozzle assembly further includes at least one valve configured tocontrol the flow of said pressurized gas.
 8. The injecting deviceaccording to claim 1, wherein said angled joint is an elbow, said nozzletube being inserted into a lumen of said elbow so as to be in line withan axis of said transport pipe downstream of said nozzle assembly. 9.The injecting device according to claim 8, wherein said nozzle tube canbe angularly positioned within the lumen of the elbow at an angleranging from approximately 0° from a centerline of said transport pipeto a maximum angle defined by contact of an outside of the nozzle tubeand an inner surface of said lumen or said transport pipe.
 10. Theinjecting device according to claim 1, wherein said nozzle tube ismanually adjustable between said fully inserted and fully retractedpositions.
 11. An apparatus for processing polymers and other materialsinto pellets comprising: a pelletizer to cut polymer strands intopellets; a dryer for drying said pellets; transport piping to transporta water and pellet slurry out of said pelletizer and to said dryer; andan injector to introduce a pellet speed expediter into said water andpellet slurry within said transport piping to enhance the speed of saidpellets through said processing apparatus so that said pellets retain ahigh degree of internal heat, said injector including a positionablenozzle tube insertable within said transport piping and selectivelymovable to different positions between a fully inserted position inwhich the nozzle tube is positioned forwardly to be within the pipingand a fully retracted position in which the nozzle tube is withdrawnfrom the piping to provide unobstructed flow of the slurry through thepiping and to prevent pellet hang-up on the nozzle tube.
 12. Theapparatus according to claim 11, wherein said nozzle tube is part of anadjustable nozzle assembly including a seal transition collar affixed tosaid transport piping, a housing attached to said seal transitioncollar, and a sliding collar that is received within said housing, saidsliding collar and said nozzle tube being freely movable within saidhousing.
 13. The apparatus according to claim 12, wherein said housingincludes a tension spring positioned circumferentially around the nozzletube and seated on a forward face of the sliding collar and a rearwardface of the seal transition collar, said tension spring being compressedas said nozzle assembly is advanced toward said fully inserted position.14. The apparatus according to claim 13, wherein said housing has atleast one groove that extends parallel with said nozzle tube, saidgroove having at least one angled recess, said sliding collar having aguide pin attached thereto that is positionable within said groove and,when received in said angled recess, locks the nozzle assembly at a setdegree of tension spring compression associated with a particularinsertion position.
 15. The apparatus according to claim 14, whereinsaid pellet speed expediter is pressurized gas and said nozzle assemblyfurther includes at least one valve configured to control the flow ofsaid pressurized gas.
 16. The apparatus according to claim 11, whereinsaid transport piping includes an elbow, said nozzle tube being insertedinto a lumen of said elbow so as to be in line with an axis of saidtransport pipe downstream of said nozzle assembly.
 17. The apparatusaccording to claim 16, wherein a clearance area between an outsidediameter of said nozzle tube and an inside diameter of said elbow lumenis large enough to allow at least two pellets, each having a maximumdimension for the pelletizer, to pass side by side therethrough withoutblockage of said clearance area.
 18. The injecting device according toclaim 1, wherein a geometric configuration of said nozzle tube is one ofround, square, rectangular, oval, polygonal, semicircular, conchoidal orC-shaped.
 19. The injecting device according to claim 18, wherein saidnozzle tube is tapered at an effluent end.
 20. The injecting deviceaccording to claim 18, wherein said nozzle tube has an inner surfacethat is spiraled, contoured, rifled, tapered or some combinationthereof.
 21. The injecting device according to claim 1, wherein anexternal surface of said nozzle tube and/or an internal surface of saidtransport pathway is surface coated or treated to prevent erosion,abrasion, corrosion, wear and stricture of pellets to said surfaces. 22.The apparatus according to claim 11, wherein an outside surface of saidnozzle tube or an inner lumen of said transport pipe is subjected to asurface treatment using at least one material selected from the groupconsisting of metals, metal oxides, metal carbides, metal nitrides, andmetal carbonitrides.
 23. The apparatus according to claim 11, wherein anoutside surface of said nozzle tube or an inner lumen of said transportpipe is subjected to at least one surface treatment selected from thegroup consisting of sintering, metallization, flame spray, thermalspray, plasma treatment, electroless nickel dispersion treatment,electrolytic plasma treatment and combinations thereof.
 24. Theapparatus according to claim 22, wherein said surface treatment fixedlyattaches metal oxides.
 25. The apparatus according to claim 22, whereinsaid surface treatment fixedly attaches metal nitrides.
 26. Theapparatus according to claim 22, wherein said surface treatment fixedlyattaches metal carbonitrides.
 27. The apparatus according to claim 22,wherein said surface treatment fixedly attaches diamond-like carbon. 28.The apparatus according to claim 22, wherein said surface treatmentfixedly attaches diamond-like carbon in a metal matrix.
 29. Theapparatus according to claim 22, wherein said surface treatment fixedlyattaches diamond-like carbon in a metal carbide matrix.
 30. Theapparatus according to claim 22, wherein said surface treatment forms acoating having a thickness not exceeding approximately 0.002 inches. 31.The injecting device of claim 3, wherein said nozzle tube in said fullyretracted position is flush with an exterior of said angled joint. 32.The apparatus of claim 16, wherein said nozzle tube in said fullyretracted position is flush with an exterior of said elbow.